XFX Radeon HD 4890 review
 

XFX Radeon HD 4890 review also featuring the Gainward Radeon HD 4870. The XFX Radeon HD 4890 has a 11% higher clock speed, 9% higher memory speed and the same 800 Pixel Shaders as the Gainward Radeon HD 4870. This means the XFX Radeon HD 4890 will be atleast 10% faster than the Gainward Radeon HD 4870. Another advantage for the XFX Radeon HD 4890 is the extra 512MB Memory which will definitely increase game performance.

http://www.ultimatehardware.net/ati/...on_hd_4890.htm